Fiat Money and Booby Birds

I DO ADMIRE BENJAMIN FRANKLIN AS the wittiest and wisest of our founding fathers. But no one would claim that he outmeasured the admirable George Washington by 100-to-1. Ulysses S. Grant may have been a fine general--forget his later (and mediocre) presidency--but could anyone argue that he outranked his commander-in-chief by a factor of 10?

Among the numerous properties and functions of money, its status as a symbol has always caught the special interest of scholars (who, like the vast majority of us, tend to have less of the stuff than they think they deserve). Although currency may be backed by something more tangible, from governmental force to the gold in Fort Knox, modern money seems to have evolved away from ancient tokens of exchange that held more intrinsic value. (The word "pecuniary" derives from the Latin pecus, or cattle--a verbal fossil of earlier forms of exchange based on inherent worth rather than symbol.)

The symbolic nature of cash stands out with special clarity in America where, unlike most European countries, we don't even graduate the size of our paper money under the venerable formula "Bigger is better." Franklin commands exactly the same area as Washington (forget the recent facial redesigns; I'm talking about the bill's outer dimensions). And if weight correlated with value, I'd ask my potential benefactor for two nickels--rather than our thin monetary substitute for a screwdriver--when I made the old plea, "Brother, can you spare a dime?"

Does the animal kingdom offer any clues about our tendency to turn physical acts into symbols? In one of the great pitfalls of human thinking about the natural world, and our evolutionary origins within this matrix, we search for analogs of puzzling human behaviors in the actions of other animals and then err in thinking that we have located the "true" explanation for the human phenomenon. By this logic--not always wrong, by the way, but badly applied in the majority of cases--if we wonder why humans seem so willing to accept mere symbols of value in executing their commerce, we should look for examples of symbolic exchange in nature, and then postulate a common source or cause.

We certainly have no trouble, given nature's virtually infinite variety, in identifying behaviors that appear, in human terms, to show creatures using objects in a symbolic manner that almost mocks the utility of the action.

Consider just two examples--the first, if you will, drawn from the world of real estate. Several species of ground-dwelling birds build fairly rudimentary nests, but booby birds of the Galapagos Islands construct no nest at all. Instead, they squirt out a ring of excrement (stark white, as with most birds) in the shape of a nest. Although this guano ring has no nestly substance, the booby parents make a sharp distinction between duties inside and indifference outside--so much so that if one of their own nestlings (or should I say ringlings?) falls outside the ring, they will never feed it again, and let it starve to death, all the while ignoring the youngster's plaintive begging that can almost break the heart of a human observer.

In several species of small flies, males wrap an item of food in silk and present the gift to a female in exchange for copulation. The female unwraps and eats, while the male engages in another vital biological activity. In one species, the males construct an elaborate package of wrapping silk--but place nothing at all inside. The female receives the symbolic gift, apparently as a token of favor in the great Darwinian mating game.

These examples seem to record a basic structural likeness, or even a similar utility, between money as a symbol of exchange and ersatz nests or mating gifts. But the birds and the bees (or, rather, flies in this case) give us no causal insight into the analogous human phenomenon. First of all, no evolutionary continuity links the fly's empty silk balloon to the suitor's diamond ring, although potential mates may find the offering attractive in both cases. These similar strategies have independent historical origin and entirely different biological foundations: a specific and genetically evolved behavior for the fly, and a nongenetic social custom, whatever the underlying evolutionary basis, for the human suitor.

More important, although we cannot enter the consciousness of another animal, we can draw conclusions about the great differences in meaning between customs rooted in human consciousness and social organization, and actions evolved for definite purposes by other organisms. The analogous behaviors in birds and bees never rest upon full abstraction, but remain firmly linked to the ancestral form and function. The guano ring looks like a nest, and the bird can continue to link a set of evolved behaviors with this ancestral context. The fly's empty package looks like the ancestral gift of real food, so the female simply retains an old behavior to receive sex without sustenance. But human money, given our unique powers of full abstraction, need not look like a cow or a jewel in order to win acceptance.

This fundamental distinction drives right to the heart of the deepest common error in our usual thinking about the relationship of humans to other animals. We understand and accept the evolutionary connectivity that unites all creatures, including ourselves of course, into one great genealogical nexus called the tree of life. We therefore recognize that our uniquely complex consciousness must have roots in the physical evolution of our oversized brains. But we rightly sense that our powers of language and abstraction, to cite only the two most obvious and significant properties of human mental specialness, so exceed what any other organism can do, including our closest relatives among great apes, that we might as well acknowledge the qualitative gap between us and all of them. How then can we square the physical continuity of evolution with this portentous chasm in mental capacity?

This classical problem in our thinking has a disarmingly simple conceptual solution. Differences so great that we choose to call them "qualitative" do not imply absence of physical continuity across the gap. In complex systems, sufficient accumulation of quantity can be translated into changes that we perceive as qualitative--"the transformation of quantity to quality," in the terminology of several classical philosophical theories, including those of Hegel and Marx. To take a familiar example, heat water sufficiently and it changes to steam as a consequence of simple quantitative increments applied to underlying chemistry and physics. The steam can then revolutionize human society by providing a source of power that water in liquid form could never supply.

Add brainpower in evolution, and these quantitative increments, applied to a vastly more complicated system, can produce qualitative wonders even beyond our present comprehension--clearly illustrated by our rudimentary Internet, and computers that can already beat the greatest human chess players. The birds and the flies remain stuck in their concrete ranges of perception and mentality. By quantitative changes in the evolution of our brains, we crossed a threshold of quality so profound that we often mistake our natural attributes and potentials for direct marks of a divine constructive power.

As one consequence of our uniquely evolved mentality, the form of our money can be purely symbolic because only we can think in such a fully abstract way--and only we can develop a society complex enough to require such a general medium of exchange in the first place. Cattle ruminate to redigest their food. But only Homo sapiens can ruminate about rumination (and other matters). And only humans could ever decree that a green picture of Ben Franklin should be worth a definite percentage of a concrete cow.

Stephen Jay Gould, a professor of zoology at Harvard University, is the author, most recently, of Questioning the Millennium.